thermal printer

When [Ch00f] was getting jeans rung up at Nordstroms, he noticed how fast thermal receipt printers can put an image on a piece of paper. This observation isn’t unique to the circles [Ch00f] frequents – there are a few small receipt paper printers out there that connect to the Internet, iPhones, and a whole bunch of other Kickstarter-friendly keyword devices.

Nevertheless, a device that can make a hard copy of an image quickly and cheaply isn’t something you just stop thinking about. After rolling the concept around in his head for a few years, [Ch00f] finally came up with the perfect build – a camera.

The hardware for the build is based around an STM32F4 Discovery board. It’s a bit overpowered for this sort of application, and this is one of [Ch00f]’s first adventures in ARM-land. The rest of the hardware consists of a thermal receipt printer and a JPEG camera, the latter of which replaced a cellphone CMOS camera module that was lost in a move.

A custom camera requires a custom enclosure, and for this [Ch00f] made something remarkable. The entire enclosure is CNC milled out of a beautiful piece of figured walnut. The end result looks far too good for a prototype, but it does polish up nicely with a bit of linseed oil.

Now [Ch00f] has an instant camera that takes the idea of a Polaroid and turns it into something that produces a print for tenths of a cent. There’s a time-lapse function – just a zip tie on the shutter button – filters with the help of highlighters, and the ability to record movies in flipbook format.

It’s a great project, and also something that will make for a great crowdfunding campaign. [Ch00f] has already started work on this. He already has a sleek, modern-looking website that requires far too much scrolling than should be necessary – the first step to a winning Kickstarter. [Ch00f] also learned a lot about ARMs, DMA, dithering, gamma correction, and the JPEG format, but that’s not going to get anyone to open up their wallet. You know what will? A slick video. You’ll find that below.

If you’re the type of person that doesn’t mind having a pocket/purse full of crumpled receipts, then maybe you should check out this tutorial from [tombrew] on giving a thermal printer internet-connectivity.

For some of us, there’s something kind of cool about thermal printers, but it’s probably not the kind of project you’d want to burn a lot of calories on. As a developer over at Electric Imp, [tombrew] agrees with this statement, but since the Electric Imp contains both a WiFi module and processor built in, it makes it pretty easy to get your thermal printer printing off the daily weather, stock prices, news headlines, etc… In fact, the claim here is that you could have this project completed before you even finish your morning coffee… knock on wood!

From a hardware standpoint, the project is pretty straight forward; an Electric Imp with breakout board, thermal printer, and a power supply are pretty much all that’s needed. Local communication between the Electric Imp and the thermal printer is accomplished through a simple serial interface. With the roll-out of the new Electric Imp IDE a few months back, we were introduced to ‘Agents’. This is kind of a neat concept, and this tutorial breaks everything down, but basically the agent is server-side code that runs in the ‘ImpCloud’, thus giving your Electric Imp more power and capabilities to deal with complex APIs. Also, handling images (like something you want to print) can take up a ton of memory, so for this project, the agent is used to send down slices of the image you want to print one at a time. This project is just the beginning of what [tombrew] has planned, so we can’t wait to see more insanely detailed tutorials.

[gbg] put together a neat little project to get people familiarized with Bitcoins. A lot of techies know what Bitcoins are, but the impetus to download the Bitcoin client and start mining is a bit too much for some. [gbg] has a solution for this – a Bitcoin vending machine. Just dump your pocket change in the coin slot, and out comes a QR code that allows you to add Bitcoins to your wallet.

Inside this Bitcoin briefcase is a Raspberry Pi that connects to a local WiFi connection. Every five seconds, the Raspi looks at the current conversion rate of USD to Bitcoins. Once coins are deposited into the briefcase, a receipt complete with a scannable QR code is printed on a small thermal printer.

When [gbg] took this to the latest DEFCON, a lot of people were interested in the project and started shoveling change into the machine. So many people were interested that [gbg] and his compatriots are planning on turning this into a proper open-source device, complete with a bill reader and possibly an ASIC miner so the Pi can sell the coins it produces.

This visually stunning tape ticker prints out [Horatius Steam’s] emails for him. It watches his email address for a secret trigger phrase in the subject line. Sure, thermal receipt printer projects are becoming rather common, but we can’t remember seeing one that took this much time and effort to make it into a showpiece.

The two parts that make this happen are the thermal printer with cutter module and the glass dome which is just large enough to house the business end of it. The driver PCB for the printer is hidden in the base (a paper tube which is painted to took like wood), which positions the outfeed near the bottom of the dome. This had the added benefit of leaving plenty of room for [Horatius] to proudly display the paper roll. Since the receipt printer is designed to work with a Windows machine there was no custom circuitry necessary.

The printer is tied to the OEM paper because of a pattern printed on the back of the roll. It’s basically an encoder strip made up of black rectangles spaced at regular intervals. Surely there are other brands that come with this pattern on them, but if you want to use paper without it the secret is in moving the sensor that reads that strip.

The brilliant solution is to use one of the white feed-gears as an encoder wheel. [CheapSkateVideo] used a magic marker to paint two opposite quarters of the gear black. He then removed the optical sensor and placed it on the side of the case facing the wheel. It needs to be adjusted along the radius of that gear until the timing is just right, but once it is you’re ready to go. The sensor is a safety feature to ensure there is media in the printer. If there’s not you can burn up the print head so keep that in mind. See the explanation in the video after the break.

Over the last year, [James] has been a part of a few commercial projects that used a thermal receipt printer as part of the build. Something must have cracked in his mind, because [James] spent a lot of time developing a way to print customized content on receipt printers, connecting these printers to the Internet, and sharing content with other Internet-connected receipt printers. Even [James] doesn’t know why he spent so much time on this project; [James] figured he was bound to find something interesting. We’ve got to commend him for that.

[James] had been aware of the Adafruit Thermal Printer Library, but this library is a little kludgy. Text is the Adafruit Library’s forte, and while graphics and non-ASCII characters are possible they’re certainly not easy to print with the existing libraries. With his current system based on HTML, CSS, and Javascript, [James] has a really easy way to print anything he can put on a webpage on receipt paper.

Getting his receipt printer onto the Internet had its own challenges. After wrangling with the Arduino Ethernet library through the month of February, [James] realized larger prints (about 15cm of paper) would fail inexplicably. To get around this, [James] wrote an HTTP client for the Arduino that would fetch data, put it on the SD card, and then start printing.

Right now, [James]’ project is a polished as anyone could hope. We’re a bit concerned – although we completely understand – that he could get sucked into the black hole of pointless development of receipt printer software so easily. All was not for naught, though; now anyone can make very professional-looking prints on receipt paper very easily.

During the gilded age, oil magnates, entrepreneurs, and robber barons would have a ticker tape machine in their study. This machine would print stock and commodity prices and chart these men’s assets climbing higher and higher. A lot has changed in 100 years, as now [Adam] can be kept apprised of what @KimKardashian, @BarackObama and @stephenfry ate for breakfast with his Twittertape machine.

Interestingly, [Adam]’s build didn’t start off as a tarnished lump of 100-year-old brass; he built his beautiful ticker machine out of old clock movements he picked up on eBay. Even though the shiny part of the build only holds the roll of paper, it’s still a wonderful build. Right now the machine is connected to Ethernet, but he’s planning on adding WiFi and a few batteries for a completely wireless build.

Unlike the other ticker tape machine we saw this week, [Adam] did away with the loud clashing of gears and solenoids found in 100-year-old ticker machines. This ticker machine prints on cash register receipt paper and a very small thermal printer in the base. Although [Adam]’s build doesn’t sound like two robots trading blows, there’s no ink needed and no danger of the letter wheel becoming misaligned and misspelling everything.